My Power Tool Shuts-Off During Use and has Problems Starting

It is no mystery that power tools can be a risky business - especially as they are beginning to wear down and parts are components are more delicate than we're accustomed to. As you also know, there are truly too many things that can go wrong with our power tools; luckily for us though, there are just as many tricks and solutions for or power tools as there are glitches and confusions. So, if you've ever wondered why your tool has trouble starting, why it will shut-down during use, or why you could use it yesterday but it won't start today, then, my friend, I'd like to extend a bit of simple advice.

With symptoms like these, it is very likely your carbon brushes or switch assembly causing all the hub-bub. Firstly, if your brushes have worn too low, if they have chipped, if burrs have formed, or if your brushes just can't make or maintain contact with the armature, it will cause your tool to start and stop, to fuss during start-ups, or to not engage altogether. Because heavy wear, chips, and burrs (or binding formations around the brush's carbon body) cause gaps in the electrical flow inside the tool, electrical flow can not complete its circuit and will either shut the tool off or prevent it from engaging.

Similarly, although a bad switch is more likely to prevent the tool from doing anything at all, before it fails completely, it may also cause the above symptoms. The most visible mischief to a power switch is heat damage which will look like burning, charring, melting or discoloration of the switch assembly. The switch may have also suffered water damage or could have simply gone kaput with the rigors of wear and tear. If, of course, your brushes can not make contact with the armature, or if the switch has been damaged, they will both require a swift replacement. If, however, your brushes and switch appear healthy, move along to the tool's armature.

Hint: If when shaken your power tool regains a bit of its spark, the problem is likely in your brushes. By contrast, should shaking return no life to your power tool, the problem is more likely in your switch.

Because a damaged commutator can cause chipping or premature wearing in your brushes, if your brushes are very badly worn or damaged, you may choose to momentarily bypass checking the switch and move directly to the armature's commutator bars. The commutator bars make contact with the carbon brushes to continue the electrical power flow in your tools and should form a perfect and perfectly smooth circle around the armature. If the armature shows any type of warping at the commutator bars like bumps, divots, or missing bars, it will cause gaps in the tool's electrical flow and unpredictable performances. Damage to the armature usually occurs during intense misuse or abuse of the tool and will spread to other components if not replaced rapidly.

Hint: For the best performances, you must ensure all your bases are covered. If you can, it's smart to check all three components when diagnosing start and stop behavior even if you find your problem early.

In the end, with start-stop action, or troubled start-ups, the most likely causes are your brushes, switch, or armature. As soon as the problem has been isolated, it can usually be a quick and simple fix. If after repairing your tool it still suffers from these symptoms (or any others for that matter) it is wise to have it more thoroughly inspected at a certified repair center.